没有死锁的Java线程挂起

Question

我目前遇到了一些问题，一个过程是悬。

首先，下面的线程转储显示没有死锁。另一件有趣的事情是，进程挂在java.lang.System.identityHashCode方法中。当前该进程的CPU使用率为0%，有时达到1%的峰值。通常情况下，该过程使用100%。它使用的是1.7GB的RAM (这对于这个过程来说是正常的)。该机器有足够的CPU，磁盘空间和RAM可用。

Attaching to process ID 4146, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 23.7-b01
Deadlock Detection:

No deadlocks found.

Thread 12761: (state = BLOCKED)


Thread 4159: (state = BLOCKED)


Thread 4158: (state = BLOCKED)
 - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
 - java.lang.ref.ReferenceQueue.remove(long) @bci=44, line=135 (Interpreted frame)
 - java.lang.ref.ReferenceQueue.remove() @bci=2, line=151 (Interpreted frame)
 - java.lang.ref.Finalizer$FinalizerThread.run() @bci=3, line=177 (Interpreted frame)


Thread 4157: (state = BLOCKED)
 - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
 - java.lang.Object.wait() @bci=2, line=503 (Interpreted frame)
 - java.lang.ref.Reference$ReferenceHandler.run() @bci=46, line=133 (Interpreted frame)


Thread 4147: (state = IN_VM)
 - java.lang.System.identityHashCode(java.lang.Object) @bci=0 (Compiled frame; information may be imprecise)
 - java.util.IdentityHashMap.hash(java.lang.Object, int) @bci=1, line=301 (Compiled frame)
 - java.util.IdentityHashMap.containsKey(java.lang.Object) @bci=17, line=358 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=18, line=346 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.FastClonerArrayList.clone(java.lang.Object, com.rits.cloning.Cloner, java.util.Map) @bci=47, line=23 (Compiled frame)
 - com.rits.cloning.Cloner.fastClone(java.lang.Object, java.util.Map) @bci=30, line=96 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=100, line=355 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.FastClonerArrayList.clone(java.lang.Object, com.rits.cloning.Cloner, java.util.Map) @bci=47, line=23 (Compiled frame)
 - com.rits.cloning.Cloner.fastClone(java.lang.Object, java.util.Map) @bci=30, line=96 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=100, line=355 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.FastClonerArrayList.clone(java.lang.Object, com.rits.cloning.Cloner, java.util.Map) @bci=47, line=23 (Compiled frame)
 - com.rits.cloning.Cloner.fastClone(java.lang.Object, java.util.Map) @bci=30, line=96 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=100, line=355 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.FastClonerArrayList.clone(java.lang.Object, com.rits.cloning.Cloner, java.util.Map) @bci=47, line=23 (Compiled frame)
 - com.rits.cloning.Cloner.fastClone(java.lang.Object, java.util.Map) @bci=30, line=96 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=100, line=355 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.FastClonerArrayList.clone(java.lang.Object, com.rits.cloning.Cloner, java.util.Map) @bci=47, line=23 (Compiled frame)
 - com.rits.cloning.Cloner.fastClone(java.lang.Object, java.util.Map) @bci=30, line=96 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=100, line=355 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.cloneInternal(java.lang.Object, java.util.Map) @bci=368, line=404 (Compiled frame)
 - com.rits.cloning.Cloner.deepClone(java.lang.Object) @bci=61, line=309 (Compiled frame)
 - arquitetura.representation.Architecture.deepClone() @bci=23, line=497 (Compiled frame)
 - jmetal.operators.mutation.PLAFeatureMutation.execute(java.lang.Object) @bci=109, line=862 (Compiled frame)
 - jmetal.metaheuristics.nsgaII.NSGAII.execute() @bci=321, line=129 (Compiled frame)
 - br.ufpr.inf.opla.patterns.main.NSGAII_OPLA.main(java.lang.String[]) @bci=1116, line=179 (Interpreted frame)

我用不同的参数执行相同的进程，时间很长(超过一个星期)。我正在使用进化算法，所以对我的问题来说，时间消耗是正常的。我执行了120次相同的进程(有不同的参数)，这个进程是第一个挂起的。目前有4个进程同时运行(计算挂起的一个)，一些甚至更多的复杂需要更多的时间。他们正在完成，我的程序正在启动其他进程，通常使用ProcessBuilder。我读过每一篇文章的输出。挂起的过程在完成不到一半的时间内输出一个正常的日志。没有错误。另一件重要的事情是，冻结进程的方法不会产生输出，所以我假设在输出消耗方面没有问题。

我的问题是:我不想扼杀这个过程，那么有任何方法可以unhang这个过程吗？另外，为什么它处于IN_VM状态(在VirtualMachine中运行)而仍然被冻结？在java.lang.System.identityHashCode方法中冻结进程是否正常？为什么它要使用我CPU的0% (很少达到1%的峰值)？

如果我能帮助任何其他的信息，请直接问，我会很高兴在这里张贴。

提前谢谢。

编辑:虽然我使用多线程，但每个线程都使用ProcessBuilder启动一个ProcessBuilder对象。因此，挂起的进程是一个单独的JVM实例，只执行一个主线程。我将输出重定向到一个文件，但正如前面提到的，这个过程挂在一个不产生输出的方法上，所以我假设输出消耗没有问题。

EDIT2:扼杀了这个过程。随后的进程已经启动并正在顺利运行。

Answer 1

这个过程没有悬念，你只是碰巧在上面发布的状态中发现了这个过程。您可以判断，因为所讨论的线程不像其他线程那样被阻塞，所以它处于正常执行中。

进程不再执行可能有不同的原因，但我可以向您保证，它们都没有与identityHashCode相关联，因为这是一个经过良好测试的内部Java函数。

着手：

• 比较几个hangups的JVM状态。如果它始终与上面相同，则问题可能与散列生成相关。若否，则：
• 张贴更多的相关代码，以便我们可以看看它。如果问题不在这一行代码中，则必须在其他地方(com.rits.cloning.Cloner听起来是开始查找的一个合理点)。
• 告诉我们你想要归档什么，有人可能会发现一个bug或者更好的方法来完成它，这完全避免了引起问题的任何东西。